Westermo MR Series - Manual (Page 280)

280 6622-3201
Web Interface and Command Line Reference Guide www.westermo.com
Confi gure > Tunnel (GRE) 4.98
When configured, a GRE tunnel will be created between 2 devices. Generic routing encapsulation
(GRE) is a means of transporting IP packets from one device to another through an unencrypted
point to-point IP tunnel. Multiple tunnels may be configured to multiple devices. The number of tun-
nels supported is dependant on the model of router.
Using the Web Page(s)
The Configure > Tunnel (GRE) page contains a number of sub-pages for Tunnel 0, Tunnel 1 etc
Description:
This parameter allows you to enter a name for this GRE instance, to make it easier to identify
it.
IP address:
This is the IP address of the virtual interface that will be used by the tunnel. Used in conjunc-
tion with the mask parameter below. This parameter MUST be entered for the tunnel to work.
Mask:
Used with the IP address parameter to clarify the subnet in use on the virtual interface. This
would normally be a 30 bit mask as this is a point-to-point link (255.255.255.252).
Interface to use for Tunnel Source IP address/
Interface # to use for Tunnel Source IP address:
These 2 parameters allow you to select the GRE tunnel source interace, so the tunnel end
point can be a physical interface rather than a virtual IP address. This is for using GRE without
IPSec. These parameters should not be used if the source address is used in the parameter
below.
Tunnel Source IP Address:
A virtual host IP address for the local end of the tunnel, configured for routing purposes. This IP
address has no other use and needs no mask as it is a host address. e.g. 1.1.1.1 Normally used
in conjuction with IPSec. This parameter should not be used if the interface is selected as the
source using the options above.
Tunnel Destination IP Address/Hostname:
This is the FQDN or IP address of the remote end of the tunnel. This could also be the virtual
host IP address for the remote end of the tunnel, configured for routing purposes. e.g. 2.2.2.2
MTU:
Maximum Transmission Unit. The greatest amount of data that can be transferred in one physical
packet. Default value is 1400.
Checksum:
This parameter selects whether to add GRE checksums to GRE packets when the unit is termi-
nating a GRE tunnel. “Off” disables checksums, “On” enables checksums.
Keepalive Delay:
When configured to a non-zero value, keepalive packets will be sent to the remote end of the
tunnel and the response is monitored to detect if the tunnel is up or down. If the tunnel is
detected as down, the routing table metric will be altered. Value is configured in seconds. If set
to zero then keepalives will not be used.